Grinding machine



Jan. 30, 1951 w. M. BURA GRINDING MACHINE 5 Sheets-Sheet 1 Filed June21, 1946 I? W9 76v 8 WALTER MARK EUR/4 Jan. 30, W. M. BURA GRINDINGMACHINE Filed June 21, 1946 5 SheetsSheet 2 gwue/wtom 9 WALTER MARKEL/R'A W. M. BURA GRINDING MACHINE Jan. 30, 1951 5 Sheets-Sheet 5 FiledJune 21, 1946 ,8 $3 WALTER MARK EUR'A Jan. 30, 1951 w, BURA 2,539,506

GRINDING MACHINE Filed June 21, 1946 5 Sheets-Sheet 4 WAL TER MARK BZJRA Jan, 3Q 1951 W. M. BURA GRINDING MACHINE 5 Sheets-Sheet 5 FiledJune 21, 1946 ml. I WALTER MARK ELJR'A mQN NON

w MS Q W9 www Patented Jan. 30,

GRINDING MACHINE Walter Mark Eura, Washington, D. 0., assignor to NortonCompany, Worcester, Mass., a corporation of Massachusetts ApplicationJune 21, 1946, Serial No. 678,195

Claims.

The invention relates to grinding machines and with regard to its morespecific features to a grinder for grinding cutting tools, bits, millingcutters and the like, especially those having tips of cemented carbide.

One object of the invention is to provide such a grinder which willshape such tools, bits, milling cutters and the like to form desiredangles of clearance without the use of a sliding tool holder or thelike. Another object of the invention is to provide a grinder of thetype indicated which will shape such tools, etc. without the use of anypatterns, blocks, cams or the like to control the generated shape.Another object is to provide relief in the direction of the feed (as ina lathe) of the tool, of constant or nearly constant angularity whilethe tool is rigidly clamped to the table of the machine.

Another object of the invention is to provide a grinder for thegeneration of relief or clearance angles in which more reliance isplaced upon the brains of the operator and less upon the skill of hisfingers.

Another object of the invention is to provide a universal grinder thatcan be set to shape many and various curved surfaces and that has meansto provide a feeding component for grinding by increased incrementswithout upsetting the generation or changing the shape of such curvedsurface.

Another object of the invention is to provide a grinder having some ofthe above characteristics which may also be used to produce ordinaryright circular cylinders, right circular cones or other common shapes.Another object of the invention is to provide a grinder with one or moreof the above characteristics which will also function as a surfacegrinder to grind a plane surface.

Other objects will be in part obvious or in part pointed outhereinafter.

The invention accordingly consists in the features of construction,combinations of elements, and'arrangements of parts, as will beexemplified in the structure to be hereinafter described, and the scopeof the application of which will be indicated in the following claims.

In the accompanying drawings illustrating one of many possibleembodiments of the mechanical. features of this invention,

Figure l is an elevation of a grinding machine constructed in accordancewith the invention;

Figure 2 is likewise an elevation of the machine, looking from the leftin Figure 1;

Figure 3 is a plan view of the machine;

Figure 4 is a sectional view, taken along the line i4 of Figure 2;

Figure 5 is a sectional view taken along the line 55 of Figure 1;

Figure 6 is a sectional view taken along the line 6- -6 of Figure 4;

Figure '7 is a sectional view taken along the line 'i'! of Figure 3.

Referring to Figure 1, the machine has a relatively low and hollow basel0 joinedto a relatively high and hollow base ll which in plan view isof narrow rectangular shape. The base l0, which is approximately square,supports a series of slides and a revolving table, while the base Hsupports a movable carriage l2. The slides and the rotatable tablesupport the work piece, while the carriage l2 supports a grinding wheell3.

Referring now to Figure 4, the base Ill has a fiat way I l and a V-wayI5 on which are located mating parts [6 and I! of a slide 2! Dependingfrom a table 2| is a large trunnion 22 which is journalled in radialball bearings 23 and 24. The outer race of upper ball bearing 23 fitswith a press fit in a hollow cylindrical portion 25 integral with anddepending from the slide 26. The outer race of lower ball bearing 24fits in a cap 25 which fits in and closes the lower end of the hollowcylindrical portion 25, whereby the ball bearings 23 and 24 areprotected from any dust in the base I0. Referring for a moment to Figurel, the cap 25 may readily be reached through adoor 2'! mounted on hinges23 on the front of the base l0.

Thus the table 2| is journalled in the slide 20 for angular adjustmentthereon, or for rotation or oscillation as may be desired. The weightof:

three ball bearings, 23, 24 and Eli are coaxial and the constructiondescribed journals the table 2 I for angular movement with very littleeffort about a fixed axis with substantially no play or lost motion.

The table 2| has a flat way 35 and a V-way 36 upon which rest the'matingparts 31 and 33 of aslide is. Referring now to Figure 6, the slide 46has a flat way 4! and a V-way 42 upon which rest the mating parts 43 andM of a table 45. The table 45 is a slide because it is movable on theways ii and 42; it is also a table to hold a work piece or a fixture forholding a work piece, as may be desired. To that end the table A5 has aT-slot it in the upper surface M thereof which is otherwise flat andhorizontal.

there is a 'l-Sl0t 5!. By means of the T-slot 46 any tool holder orother fixture, and certain work pieces may be rigidly clamped to thetable 45.

Likewise in one side surface 56, which is otherwise fiat and vertical.

The T-slot I adjustably holds a dog 52 the purpose of which will belater explained.

Referring now to Figures 1 and 2 on the front of the machine is ahandwheel 55. This handwheel 55 is secured to the front end of a screwshaft 55 which is shown in cross section in Figure 4. As shown in Figure2 a collar 5! is secured to the screw shaft 55, and the collar 5'! abutsa thrust bearing 58 through which the screw shaft extends and in whichit is journalled. The bear in; 58 is attached to the front of a box 59fastened to and extending forwardly 'from the front. of the base I0. Inthe box 59 is a collar, not shown abutting the other side of the bearing'58.' Thus the screw shaft 56 is held against axial movement. It passesthrough a pair of nuts 60, only one of which is shown inFigure 4, whichnuts are formedin'tegral with the cylindrical portion '25. The nuts 60arefai'rlythin and can be flexed toward each other by a bolt 6| in ordertorernove play between the 'nuts and the screw shaft 56. By'tur-ning thehandwheel 55 the slide 20' can'be moved, and also accurately adjusted.The slide 40 is similarly adjustable and movable'upon the table 2| andlikewise the table45 is adjustable and movable upon the slide 40. As

shown in Figures 1, 2, 3, and 4 there is a hand wheel @5 on one "end ofthe slide 40 which is fastened to a screw shaft 66 'which passes througha nut G Tsecured to the table 2 l. The screw shaft 66 journalled in a"thrust bearing, including a collar 68 fastened to the shaft 66 and apart 69 of theslide40.

Referring now to Figures 1, 3, and 4 there are a pair of hand wheels 10secured to the ends of ascrew sha'ft H which'is journall'ed in dependingportions "I2 of the table 45. 'Collars I3 and 14 hold screw shaft IIagainst axial movement relativeto the table 45' Screw shaft 'iI passesthrough a nut I5 which extends upwardly from andis formedintegrally withthe slide 40.

""It is important't'o be able to lock the revolving table 2I in anydesired angular position. To this endfas' shown in Figure 4', I providea lever I6 journalledon 'a stud'll, the lever 16 having a partiallgear123 formed thereon which meshes wane gear 19 which is secured to a shaft80' upon which is a cam BI. When the lever 16 is turned, cam 8.I isrotated and wedges the table 2|.

It. is also desirableto be able to set the table- ZI at a given angle'without the use of instruments. To that'end on the conical surface 84-of the table 2ifare a number of lubherlines 85 andupon the conicalsurface 860i the. slide 20 are scale marks. Further, to facilitate thesetting of the table 25, I providev a T-slot 88 for adjust'ablevsecuring a number of dogs 89 which. have, arms 90, pivotally mounted atM. These arms 90, when lowered, engage the upper endlof a" stop. 92extending upwardly from the cylindrical. portion 93 of the slide 20.This cylindrical portion 93 of slide 20 merges into the conical portion86. 9:2 is shown in the drawings, but several dogs 89 and arms. fliimaybe provided and, if desired, more thanone st peZ. The dogs 89 aremovably mounted on T-bolts 94 which extend into the 3-519 5 Referringnow to Figure 3, means are provided accurately to adjust the position ofthe slide 20. A bracket 95 is secured to'the base I0 and has an openslideway 97. secured a dial micrometer gauge. 98. Blocks 99 mhylbeplaced in the slideway 91, these blocks being of designated length tover close toler Only one dog 89, arm 90 and stop.

To the bracket Edis.

ances. A dog I00 located in a T-slot, IOI, Figure l, in the slide 26engages either a block 99 or the needle'of the dial micrometer. gauge 98and thus the slide 20 may be adjusted to various exact positions andreadjusted by small increments. ""Similarly the dog 52 in the T-slot 5|of the table45 may engage a block I02 in an open slideway I03 of abracket I04 attached to the slide 40, or it'may engage the needle of adial micrometer gauge I05, for the accurate adjustment of the table 45.7 7

Referringnow to Figures 1 and 5, the high hollow base II has a dovetailportion IIO on the top of which is a flat slideway I I I. Opposite thisdovetail portion H0 is another dovetail portion II2' likewise having a'fiat slideway H3 on the top thereof; The carriage I2 is a hollowrectangle in cross section and the lower "wall I I4 thereof has a smoothplane surface on the bottom which rests upon the slideways III and I I3.'E'xtending downwardly from the ends ofthe lower. wall H4 areouterdovetail portions [I5 and H6 which 'mate with the dovetail portionsII-Uand II 2. Gibs II? adjusted bybolts H8 complete the slideway for thecarriage I2 which can thus move freely on the base II in 'a straighthorizontal line but is firmly held from any side'motion. The carriage I2may also be locked rigidly in position bymeans of a sCreWIZU extendingthrough a stationary nut I2! extending downwardly from the top wall I22of the carriage I 2, as the screw I20 abuts alever I 23 which is mount-'ed on a pin I24, and the lower end'of the lever engages a gib HT. "'I'hepi'n I24 is held by ears extending from the sidewall 525 and the bottomwall H4 Referring now to Figures 5 and '7, bolted to thelower wall I I4by means of bolts I20 is a casting: I29. This castingI2'9 holdsacylinder I30 in which is apiston ISI connected by hollow piston rodsI32, to brackets I33 which are hollow and admit and exhaust fluidto andfrom the hollow rods I32. The brackets I are mounted on the base I I andhave the double of: holding the rodsl 32 and transmitting fluid. Thecarriage I2 can be automatically recipr ocated by means of the pistonand cylinder unit I3I and; I 3 0 which can be controlled by arever'slinglever I34 (Figure l) pivoted at I25v which is engaged by.reversing dogs I35 adjustably mounted in a, T-slot I31 on theosicle vof, the carriage I2. The speed of travel of the, carriage [2 can beadjustedby means. of a knob l't flwhi'chisturned to change the settingof a valve, and the carriage can, be started and stopped by means of alever I39 which, pulls the knobT-jid; out or pushes it. in. The variousvalves and the hydraulic diagram are. not. herein disclosedbecause suchare now well known inthe art I prefer to usethe. Norton hydraulic systemas disclosed, for example, in U. S. Patent No.. '2, 0. 71, 67' '7, whichis hereby incorpo ed by r ference. i

Sometimesit is desirable. to .mOYQithe carriage I2 by hand. Referringnqwto Fisureb, theidove tails 1m and H2, areconnected y, castinsnorr.tion I40 which is a,v U-shaped inIcross, section and in one side wall ofwhich are boresfor a shaft I andra stud I45. Ontheshait I45 are spurgears I41.and I48, the.,f,Qlfr ner' eshingwith a rack I which isfastenedto thecasting I29. Gear I48, meshes with a gear .I'5I'on"thestud I45, and gear I5I meshes with gear I52. The gear I52 has a clutchportion I53 which can be'engaged by a clutch portipn l54on thejend, of ahub I55 of a handwheel I56; Thehub I55 5, is slidably and rotatablymounted in a bore I51 in the front wall of the high hollow base II.Through the hub I55 and through the gear I52 and into a bore I58 in thecasting portion I40 extends a shaft I59 which abuts a spring I60. Whenthe handwheel I56 is pushed, the clutches I53 and I54 engage, and thenby turning the handwheel I56 the carriage I2 can be traversed on thebase II. The spring I60 automatically disengages the clutches I53 andI54 when the handwheel I56 is released. A pin I6I extending into agroove I62 in the hub I55 prevents the handwheel I56 and shaft I59 frombeing accidentally removed from the machine.

Referring now to Figures 1, 3, and 7 on the front of the carriage I2 area pair of dovetail portions I65, I65 forming a slide way upon which ismounted a vertically movableslide I66 having co-operating dovetailportions I61, I61. Gibs I68 and bolts I69 are provided for the jointpurpose of eliminating lost motion and locking the slide I66 in adesired vertical position.

On the side of the carriage I2 is a handwheel I which is secured to ashaft I1I which is suitably journalled in the carriage I2. The shaft IIIextends into a hollow box portion I12 formed in the forward part of thecarriage I2. This box portion I12 includes a separate casting I13 inwhich are formed upper. portions of the dovetail portions I65. Thisseparate casting I13 is provided for purposes of assembly. The boxportion I12 on its lower side supports a ball thrust bearing I15. Thecasting I13 receives the thrust of a ball thrust bearing I16. Thesebearings I and I16 support a sleeve I11 having formed in the centerthereof a worm wheel I18. With this worm wheel meshes a worm I19 whichis keyed to the shaft I1I.

The sleeve I11 is internally threaded and receives a screw shaft I80,the top of which is fastened by means of a nut I8I and washers I82 to anoverhanging portion I83 of the slide I66. It will thus be seen that theslide I66 may be raised or lowered by turning the handwheel I10 and itmay be locked in position by tightenin the bolts I69.

Referring now to Figures 1, 2, 3 and 7, on the front of the slide I66 isan integral hollow trunnion I85 (see especially Figure 2) journalling asplit bearing I86 of a wheel head support I81. A hand lever I88 isfastened to a vertical shaft I89 which extends through integral bossesI90 and I9I formed on the split bearing I86 on either side of the split.The shaft I89 is free in the boss I90 but in screw threaded engagementwith the boss I9I. Therefore the bearing I86 may be tightened upon thetrunnion I85 to lock the parts together or may be loosened to adjust thewheel head support I81 angularly about a horizontal axis, by moving thelever I88. A lubber line I92 is provided on the bearing I86 and scalemarkings I93 are provided on the trunnion I85 in order to adjust thewheel head support I81 to known angles.

The wheel head support I81 extends away from the trunnion I85 andterminates in a hollow bearing I95 the tranverse plane of which ispractically tangent to the trunnion I85. Furthermore, when the zero markof the scale I93 is on the lubber line I92 this transverse Plane ishorizontal and the axis of the bearing I95 is vertical.- A trunnion I95of a wheel head I91 fits in the hollow bearing I95. The wheel head I91supports a motor I98 which drives a shaft I99 journalled in a bearing200 in the wheel head I91. The

grinding wheel I3, which may be a cup wheel as. shown, or may be aperipheral wheel or of any other shape, is fastened to the shaft I99.

The trunnion I96 is held in the bearing I95 by means of a bolt 202 whichextends through a boss 2% formed in the wheel head support I81 and intoa threaded boss 284 in the center of the trunnion I96. The bolt 202 maybe loosened to adjust the wheel head I91 angularly, and tightened tosecure the adjustment. It will be noted that there is room to swing thewheel head I91 through a full circle in some positions of the wheel headsupport I81. The former has lubber lines 205, and the wheel head supportI81 has scale markings 206 in order accurately to determine the angle ofadjustment of the wheel head I91. When the zero of the scale markings206 is on one of the lubber lines 205, the axis of the wheel I3 isperpendicular to the slideway III, II3.

In order to grind a single point tool such as a lathe tool which willhave relief or clearance angles in the direction of feed of the toolinto the work it is to out which are of nearly constant angularity, Iprovide a tool or work holder (not shown) which may be rigidly securedin the T slot 46 in the surface 31 of the work table 45. Such a workholder will be capable of holding the tool to be ground in any angularposition. I place the tool in the tool holder and position it so thatthe shank of the tool is normal to the direction of feed of table 65. Inorder to grind the side under the side cutting edge to the requiredrelief angle, that is, the side longitudinal of the shank of the tool, Iindex the wheel I3 to zero by moving the wheel head I91 about itsvertical axis until the lubber line 295 comes op-. posite the zero markof the scale markings 206. In this position the axis of the wheel willlie in a vertical plane which is parallel to the direction of infeed ofthe lowest table 20. I then tilt the wheel I3 to the angle to which Iwish to grind the relief under the side cutting edge of the tool bymoving the wheel head I81 about the, horizontal trunnion I until thelubber line I92 comes opposite the angle of tilt I desire on the scaleI93. The face of the wheel I3 will then lie in the required angle fromthe vertical. To obtain the desired angle of relief under the frontcutting edge of the tool to be ground, I tilt the tool from thehorizontal through an angle which is the difference between the side andfront relief angles required by adjusting the holder. To form a radiusat the corner of the tool wherethe cutting edges meet, I back away thelower cross slide 20 from the wheel face by means of wheel 55, until thecenter of the table 2I is away from the wheel face by the amount of therequired radius, as indicated by the dial micrometer gage 98. The radiuswill also depend upon the height. of the tool edge with respect to thewheel face because the wheel has been tilted. This has been taken intoaccount when the micrometer gage 98 is indexed. I then set the revolvingtable stops 89 so. that the table ZI will swing the tool through anangle at one limit of which its side cutting edge is pre sentcd to theface of the wheel I3 and at the other limit of which its front cuttingedge will be presented to the face of the wheel I3. In setting the limitstops 89 I determine the limits of. the angle of swing of table 2i toadjust the stops 89 by bringing the lubber line 85 opposite the properreadings on the scale 86. I feed the tool longitudinally into the wheelto present the front cutting edge by advancing the table 40 with thewheel 65;

and I feed the side cutting edge in by advancing the cross slide 45 withwheel toward the wheel l3 when the side cutting edge is turned towardthe wheel face. To grind the radius where the cutting edges meet Irevolve the table 2! between the stops 89. The amount of stock to beremoved depends upon the amount I feed the tool into the wheel I 3 bythe tables 40 and Q5 or the re 'sultant' of these motions. No matter howmuch I feed the tool into the wheel I3 by advancing tables 40 or 45, Iwill grind the same radius and the same side and front cutting edgerelief angles for which I set the machine up. Feeding in the tool bymoving the tables 46 and 4% simply causes more stock to be removed, butthe resulting shape of the cutting edges of the tool will remain thesame. It will be seen that by rotating the tool upon the table 2|against the face of the wheel l3 as I grind the radius, thepredetermined relief angle-under the side cutting edge of the toolautomatically changes to the angularity I have set for the relief underthe front cutting edge of the tool.

To grind a multiple toothed tool such as a peripheral and face mill toobtain constant ang ularity of relief in direction of feed (of the tooltoward the Work it cuts) I provide a work holder which is capable ofholding the shank of such a cutter tool to the wheel face at any angle,and I clamp it to the Work table 35 by means of the T slot 46. I placethe tool therein, so that its shank lies horizontally and in a verticalplane which is at right angles to the direction of feed of the Worktable 45. I index the wheel is about its vertical turning axis to zeroas before, so that the wheel spindle lies in a vertical plane which isparallel to the tableway 2B, and I tilt it about its horizontal axis tothe angle of relief (from the vertical) I desire the face of the tool tohave. I then rotate the table 2| to position the face cutting edgeagainst the wheel by advancing table so by means of wheel 65. I limitthe rotation of table 2! at this position by setting a limit stop 88. Ithen rotate the table 2| to present the peripheral cutting edge of thetool to the wheel face by advancing table 45 with wheel 78' and I limitrotation of table 21 to this position by setting another limit stop 89,so that the table 2! can now rotate between these two angle limits togrind the face, the radius and the peripheral side of the tool in onepass. In order to further support the tool while it is being ground atooth rest (not shown) integral with the wheel head is provided tosupport the particular tooth being ground from beneath at the point ofgrind. To grind the angle of relief desi'redon the peripheral face, thetooth rest is adjusted up or down (as the set up indicates) the tool isrotated on its axis through an angle which is equal to the differencebetween the two cuttin edge relief angles I desire. I back the table 21away from the face of the wheelv 13- on its slide 29 by means of feedwheel 55 so that its center lies away from the wheel face anamount equalto the radius I Want at the corner between the face and peripheralcutting edges of the tool. This will produce the required angle ofrelief under the peripheral cutting edge. For example, ona cutter toothrequiring 3 relief in the face cutting edgeand 7 on the peripheralcutting edge, the wheel would be tilted 3 from the vertical and thetooth rest lowered through an angle of i. The change from: one angle tothe other is accomplished automatically as the table 2;! is rotatedbetween the limit stops as as set to grind the radius, which results in:the shape of a right truncated cone on the corner where the radius isground. I

"These two illustrations of the machine operation describe functions forwhich this machine is particularly well adapted. In surface grinding thewheel 13 will automatically traverse the work as it moves on itshydraulically driven carriage I2, while set at any angle of tiltdesired. Infeed is controlled by the movable tables as described above,and depth of cut by the wheel I10 to lower the wheel vertically. Theseven motions in the machine to control movement of the wheel and thework (exclusive of work positioning by means of a tool holder not shown)relative to each other together with micrometer gages allow controlledgrinding of an infinite number of shapes without the use of templates,patterns, cams or the like.

It will thus be seen that there has been provided by this inventionapparatus in which the various objects hereinabove set forth togetherwith many thoroughly practical advantages are successfully achieved.

As many possible embodiments may be made of the above invention and asmany changes might bemade in the embodiment above set forth, it is to beunderstood that all matter hereinbefore set forth (or shown in theaccompanying drawings), is to be interpreted as illustrative and notin'a'limiting' sense.

I claim:

H 1. In a grinding machine, a base, a slide direct ly upon said.- base,a rotatable table directly upon said slide, a second slide directly uponsaid ro tatable table, a third slide directly upon said second slidemovable at an angle to said second slide, a second base connected tosaid first base and extending above it, a horizontally sliding carriageon said second base, a vertically movable slide on said slidingcarriage, an angularly adjustable wheel head support on said verticallymovable slide adjustable about a horizontal axis, and a; wheel headcarried by said wheel head supportand angularl y adjustable about anaxis normal to the axis of said wheel head support, the wheel head beingover the table whereby a grinding wheel mounted thereon may operate upona Work piece held by said third slide.

2. In a grinding machine, a base, a slide mov: able on said base, ahollow cylindrical portion extending downward from said slide into saidbase, a table, a downwardly extending trunnion under said table, meansfor journalling said trunnion in said hollow cylindrical portion wherebysaid trunnion is angularly movable, additional thrust bearing meansbetween said slide and said table for supporting said table from saidslide, a slide carried by said table which is movable in a planeperpendicular to the axis of said trunmen, and a further slide on theslide carried by said table, saidfurther slide being movable in a planeparallel to but in a direction at an angle to'the slide carried by thetable.

3. In a grinding machine; a base havinga' low portion and a portion, ahorizontally sliding carriage mounted upon said high portion, avertically'movable slide carried by said carriage, a wheel head supportjournalledon a horizontal axis in said slide; a wheel head journalled insaid support on an axis normal to said horizontal axis, a slidemounteddirectly upon the low portion of said-base, an-angularly adjustabletable mounted sheen-yon: said slide which is upon the low por tion ofsaid base, and a pair of slides one above the other on said table, saidslides on said table 9 being movable at an angle to each other but inplanes parallel to each other, and the wheel head being over said table,whereby a grinding wheel carried by the wheel head can operate on a Workpiece held by the top slide of the pair of slides one above the other onsaid table.

4. In a grinding machine as claimed in claim 3, the combination with theparts and features therein specified, of means for feeding each of saidslides.

5. In a grinding machine as claimed in claim 3, the combination with theparts and features therein specified, of means for accurately locatingsaid table and means for accurately locating one of said slides.

WALTER MARK BURA.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

